1. Summary of the Invention
The present invention relates to an adjustable and removable neck for a stringed instrument allowing disassembly as well as string action changes without disassembly.
2. Description of the Related Art
The most popular traditional banjo design over the last 50 years is referred to as the “Pre-War design” originally introduced by Gibson Instruments in the 1920's and 1930's. This design employs 24 hooks and nuts, a tension hoop, and a one or two piece flange attached to the circular wood and metal tone chamber called the pot. The pot assembly in turn is affixed to an immovable neck which is oriented to the pot at one specific angle. The most popular pre-war design employs two coordinator rods that span the interior of the pot and provide attachment points for a stable neck connection. The only neck angle adjustment available to owners of double coordinator rod banjos is to use the threaded ends of the rods to push or pull the pot out of cylindrical roundness in order to warp the pot enough to change the orientation of the neck angle to the playing surface or head. Needless to say this warping action is not an effective adjustment and can cause damage to the instrument.
The height or spacing of the strings above the fingerboard, often referred to as “action”, is generally controlled by the height of the bridge and the angularity of the top surface of the neck relative to the body of the instrument. Tilting of the neck downwardly relative to the body of the instrument serves to bring the strings closer to the finger board and thus lowers the action. Conversely, tilting of the neck upwardly relative to the body tends to move the strings further away from the fingerboard, thus raising the action. The string/fingerboard spacing is generally a matter of personal preference for the player of the instrument. There is a range of desired action for an individual player. The preference is for the player to be able to maintain the action of the instrument as desired.
Various means have been suggested over the years to deal with neck angle adjustment in guitars, banjos and other stringed instruments. Banjoes made by Gretsch, and Harmony had a concave radiused portion on a banjo pot that mated with a concave end of the banjo neck whereby pivoting of the neck along the radius caused changes in the neck angle and resulting string action. The trouble with this adjustment was its tendency to slip, and the fact that in order to tighten up the connection it was necessary to remove the instrument's back to tighten the neck's fastener. Another problem with the above the adjustment is that its inherent geometry causes the fingerboard surface to tend lower in relation to the head surface as the string action (or height) is increased. Therefore if a low bridge is employed to hold the strings and proper sting action on the neck is achieved, there will be insufficient space for the clear picking of the strings without hitting the head.
There are numerous examples in the prior art of devices and systems for adjusting the action of a stringed musical instrument. Various stringed musical instruments having mechanisms or devices for permitting adjustment of the inclination of the neck. U.S. Pat. No. 6,265,648 describes a spring-loaded clamping device securing the neck to the body while permitting limited pivotal movement of the neck relative to the body. The clamping device includes a spring arranged to provide a biasing force and an adjustment member moveably mounted on either the neck or the body so as to move in a direction opposing the biasing force of the spring and adjusting the angular position of the neck relative to the body, thus adjusting the action of the instrument. In addition, U.S. Pat. No. 6,831,218 describes a movable adjustment member to adjust the angular position of the neck with respect to the instrument. The movable adjustment member may be finger manipulable and accessible through a sound hole as in an acoustic guitar. In addition, U.S. Pat. No. 7,157,634 allows a player to change the vertical height of the instrument's neck without affecting the angle of the neck relative to the guitar body and thus not affecting intonation or scale length. The invention has a height adjustment screw in back of the body and extending perpendicular to the neck which engages the body with the neck and allows adjustment of the vertical height of the neck relative to the body.
Many musicians prefer different action heights for different musical styles, and hence desire a means for changing of the action of their instruments quickly and conveniently, and in some instances even during a performance. A need exists for an adjustable neck on a stringed instrument which enables quick and easy neck angle adjustment for adjusting the action of the strings without requiring disassembly of the stringed instrument. A need also exists for a detachable neck on a stringed instrument for easy transportation of the stringed instrument.